The principal goal of this work is to study the biochemical, biological, and biophysical characteristics of the replication of respiratory syncytial (RS) virus. An effective purification scheme has been developed which yields virus of high purity which is still infectious. The virus consists of at least eight polypeptides. The genome RNA is 50S. There are at least seven virus-specific polyadenylated messenger RNAs. The kinetics of virion and virus-specific messenger RNAs are to be studied. Further studies are also underway to determine which viral polypeptides are glycosolated and to determine, if possible, the location of the individual polypeptides within the virion and their functions.